Copy theora/win32/experimental/transcoder/transcoder_example.c to theora/examples/encoder_example.c - this will replace the usual Theora encoder example with the application creating a Theora stream from the raw VP3 data.

Copy theora/win32/experimental/transcoder/transcoder_example.c to theora/examples/encoder_example.c - this will replace the usual Theora encoder example with the application creating a Theora stream from the raw VP3 data.

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Configure your copy of Theora (run autogen.sh). This has a few dependencies. The configuration process will guide you. Be patient. Once configuration didn't complain because of missing dependencies: Invoke make.

Configure your copy of Theora (run autogen.sh). This has a few dependencies. The configuration process will guide you. Be patient. Once configuration didn't complain because of missing dependencies: Invoke make.

Line 41:

Line 38:

theora.ogg now should be a valid Theora + Vorbis Ogg file. Congratulations!

theora.ogg now should be a valid Theora + Vorbis Ogg file. Congratulations!

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== Bugs ==

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If the VP3 video input has dropped frames (this is common on broadcasted videos with narrow bandwidth constraints) you may notice that the created Theora file is distorted in affected parts of the video (apparently because the information that frames were dropped is lost, thus some video frames predict from the wrong predecessors).

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[[Category:Theora]]

Latest revision as of 14:59, 6 July 2008

This is a quick guide to show how to transcode VP3 (usually with MP3 audio) to Theora.

Now, this quick guide involves a lot of tools which are either experimental or are known to be buggy. Beware. Use with caution.

Get the Theora code

Build the avi2vp3 tool

Go to theora/win32/experimental/transcoder/avi2vp3/

Compile the tool which will extract the VP3 data out of your AVI file: gcc *.c -o avi2vp3

Build transcoder_example

Copy theora/win32/experimental/transcoder/transcoder_example.c to theora/examples/encoder_example.c - this will replace the usual Theora encoder example with the application creating a Theora stream from the raw VP3 data.

Configure your copy of Theora (run autogen.sh). This has a few dependencies. The configuration process will guide you. Be patient. Once configuration didn't complain because of missing dependencies: Invoke make.

After everything compiled you should rename the encoder_example binary (which is in the examples directory) to e.g. transcoder_example to avoid confusion.

Process your videos

Use avi2vp3 to convert your VP3 AVI. The input file *must* be named vp31.avi, the output file will always be outfile.vp3

The audio will be in audiodump.wav. Encode it with e.g. oggenc: oggenc -q 1 audiodump.wav

Now you need to combine video.ogg and audiodump.ogg. Use oggzmerge from the oggz-tools package (at least in Ubuntu it's oggz-tools): oggzmerge video.ogg audiodump.ogg > theora.ogg

theora.ogg now should be a valid Theora + Vorbis Ogg file. Congratulations!

Bugs

If the VP3 video input has dropped frames (this is common on broadcasted videos with narrow bandwidth constraints) you may notice that the created Theora file is distorted in affected parts of the video (apparently because the information that frames were dropped is lost, thus some video frames predict from the wrong predecessors).